The present invention relates to devices and methods for providing supplemental chemical additives to fuel systems, for example, engine fuel systems, such as those of automobiles, trucks, heavy equipment, and the like, and fuel delivering and dispensing systems.
Internal combustion engines are still the predominant means for propelling motorized vehicles. They are proven to offer many advantages over alternative mechanisms, among these being cost and convenience, however, they also present a number of increasingly concerning limitations. For instance, incomplete combustion of hydrocarbons remains a problem, leading to ozone production and air pollution. This can be countered somewhat by reducing engine tolerance and increasing the temperature of combustion, but doing so exerts an adverse impact on the materials of the engine. It then becomes desirable to add combustion enhancers, such as ferrocene, and friction inhibitors, and the like, to the fuel. Also, whenever fuel sits for an extended period of time or is exposed to air, thermal degradation products and bacterial slime can accumulate, which must be removed by the fuel line filter. A build-up of these undesirable products can be mitigated with the use of antioxidants and microbicides. Other performance-enhancing additives, e.g., for reducing pollution and/or increasing fuel efficiency, can also be added beneficially to the fuel.
Various methods of introducing additives to vehicle fluid systems, generally, have been proposed. Rohde U.S. Pat. No. 3,749,247 describes a container for releasing an oxidation inhibitor into hydrocarbon-based lubricating oil in a working engine. The oxidation inhibitor is held in a polyolefin container that permits the additive to permeate through the container wall into the oil. A further approach is described by Lefebvre U.S. Pat. No. 5,591,330, which discloses a hydrocarbon oil filter wherein oxidation additives in a thermoplastic material are mounted in a casing between a particle filtering material and a felt pad. Reportedly, the thermoplastic material dissolves in the presence of high temperature oil thereby releasing the additives. Additionally, an additive release device for use in an engine fuel line is proposed by Thunker et al U.S. Pat. No. 5,456,217. The latter device comprises a partially permeable cartridge positioned in the filling neck of the fuel tank so that whenever fuel is added, a portion of the additive contents of the cartridge is released into the tank. Furthermore, a fuel filter having integral means for releasing a fuel additive is proposed by Davis et al U.S. Pat. No. 5,507,942. This device attempts to prolong filter life while also providing a constant level of fuel additive by balancing exposure of the filter media to fuel and supporting the fuel additive in contact with the fuel.
The above-described devices suffer from a variety of limitations, such as unsuitability for fuel line systems, operating only when fuel is added to a tank, or insufficiently controlling delivery of additive to the fuel. It is an object of the present invention to provide an alternative, relatively low-cost device for releasing chemical additives into a fuel system at a constant rate, which requires minimal human intervention.
New apparatus and methods for providing release, preferably sustained release, of at least one additive into a fuel composition have been discovered. The present apparatus and methods effectively provide for sustained, preferably substantially controlled, release of additive into a fuel composition. The present apparatus and methods provide straightforward approaches to releasing the additive into fuel in vehicle fuel systems, as well as into fuel being delivered and dispensed.
Many components of the present apparatus, other than the additive or additives, are substantially insoluble in the fuel composition, so that these components remain intact and do not dissolve into and/or otherwise detrimentally affect the fuel and fuel system. In addition, several of the components of the present apparatus can be reused after the fuel additive has been spent, that is substantially completely released into the fuel. The present apparatus is easy and straightforward to manufacture cost effectively and can be used in fuel systems with little or no modification.
In one broad aspect, the present invention is directed to fuel additive containers for use in fuel systems, for example, associated with vehicles, fuel delivery or delivering systems, fuel dispensing systems and the like, which are designed to provide sustained or gradual, preferably substantially controlled, release of at least one additive(s) into a fuel composition. The present containers comprise a fuel-impermeable casing defining a substantially hollow interior and at least one opening. A fuel additive composition comprising at least one chemical additive soluble in fuel, for example, at least one fuel-soluble supplemental additive, is provided in the interior of the casing. The fuel additive may be provided in the form of a liquid, gel, paste, or in solid form. In one particularly useful embodiment of the invention, the fuel additive composition is provided as a plurality of particles, or in particulate form, for example, in the form of beads, tablets, pellets, grains or other particulate form.
The casing and other fuel-impermeable components of the apparatus of the present invention are preferably composed of materials selected from suitable metals, fuel-insoluble polymeric materials, combinations thereof and mixtures thereof. Useful casings can be made of materials selected from metals, such as steel, aluminum and the like, polyvinyl chloride, polyethylene, polypropylene, nylon, polyethylene vinyl acetate (EVA), polypropylene vinyl acetate (PVA), combinations thereof and mixtures thereof, and the like.
The containers of the present invention also include at least one fuel-permeable element or component which is provided at or near the at least one opening of the casing. This fuel-permeable element is effective to provide for At release of a portion of the chemical additive composition in the casing into a fuel composition, for example, a liquid fuel composition, such as a liquid hydrocarbon fuel composition, in contact with the casing. Such release occurs over a period of time so that a portion of the chemical additive is retained within the casing, at least after the initial release of additive occurs. The additive release obtained in accordance with the present invention preferably is sustained additive release.
In one embodiment of the invention, the casing is substantially cylindrical in shape. The casing includes at least one opening, for example, at an end of the casing or in a side wall of the casing, where fuel is allowed to contact a portion of the fuel additive composition contained within the casing. For example, an end cap can be employed which cradles or attaches to the open end and retains the fuel additive composition within the casing. In one embodiment of the invention, the cylindrical shaped casing includes two open ends, each open end being covered by an end cap. The end cap preferably comprises a fuel-impermeable material and is effective to retain the fuel additive composition within the casing. The end cap includes one or more inlets or openings for allowing fluid communication between fuel composition located exterior to the casing and the fuel additive composition within the casing to permit the release, for example, by diffusion or otherwise, of the chemical additive into the fuel composition, preferably at a substantially controlled rate.
In a more preferred embodiment, the casing is substantially bowl-shaped in form. The at least one opening may be located at any point of the casing, for example, on the top of the casing, in a side (side wall) of the casing and/or in the bottom of the casing. In one useful embodiment, particularly when the bowl-shaped casing has an open end, for example, an open top end, a cap member may be included which provides means for retaining the fuel additive composition within the casing interior. The cap member advantageously is made of polymeric material and includes at least one inlet or opening, and preferably a plurality of inlets or openings, for allowing contact between the fuel additive composition and the fuel composition. The cap member may be secured to an interior surface of the casing, and may be somewhat recessed therein. In one embodiment of the invention, the cap member is removably secured or removably sealed to the casing, for example, by means of an o-ring or other suitable, e.g., conventional, sealing element or assembly. In addition, a plate member may be provided and fixed within the bowl-shaped casing. The plate member includes one or more plate inlets which substantially align with the cap member inlets. The plate member may be made of any suitable fuel-insoluble material.
In one embodiment, the container of the present invention comprises the bowl-shaped casing having both the cap member and the plate member disposed across the container open end. A fuel-permeable element is disposed, or sandwiched, between the cap member and the plate member.
The fuel-permeable element(s) or component(s) may comprise any suitable fuel-permeable structure, and all such structures are included within the scope of the present invention. In one particularly useful embodiment, the fuel-permeable element or component comprises a filter member or filter media, for example, a porous or semi-permeable membrane.
The porous or semi-permeable membrane of the apparatus of the invention may be made of any suitable material that permits the desired, preferably sustained, release of chemical additive into the fuel, particularly when the casing is in contact with fuel. The membrane can be made of a fuel-insoluble material, for instance, having irregularly-sized channels or discrete-sized pores therein. As used herein, a xe2x80x9cporousxe2x80x9d membrane refers generally to membranes having pores in a substantially discrete size range, such as a wire screen or filter media, for example, filter paper and the like. As used herein, a xe2x80x9csemi permeablexe2x80x9d membrane refers to a continuous medium, which does not have pores in a discrete size range, but instead preferably permits diffusion of molecules through narrow channels, the size of which can be difficult to measure.
In one embodiment, the membrane, for example, the porous or semi-permeable membrane, comprises one or more glasses and/or one or more polymeric materials and/or one or more papers and/or the like, combinations thereof and mixtures thereof. Very useful membranes can be made of materials selected from nylon, cellulose acetate, cellulosic polymers, glasses, polyester, polyurethane, polyvinyl chloride, polyethylene vinyl acetate, polypropylene vinyl acetate, natural and synthetic rubbers, and the like, combinations thereof and mixtures thereof.
Alternatively or additionally, the fuel-permeable element(s) or component(s) can include a fuel-soluble material, such as in the form of a dissolvable, that is, fuel-dissolvable, seal, which dissolves, for example, gradually, in the presence of the fuel to effect release of the additive from the casing. The dissolvable seal may comprise, for example, a fuel-soluble polymer seal. Preferably, although not necessarily, the at least one fuel-permeable element includes a support structure, for example, a wire screen or cloth or other fuel-insoluble material, which may be coated with a fuel-soluble polymer to form a suitable seal structure. Alternatively, the dissolvable seal may comprise the fuel soluble polymer alone, without such a support structure. It is also noted that the membrane can be coated, e.g., with a polymeric material or a fuel insoluble polymeric material, such as a fuel-soluble polymeric material or a fuel-insoluble material, in order to more effectively control release of additive from the container into the fuel.
In another broad aspect, the invention is directed to methods for releasing a chemical additive, preferably at a sustained, more preferably substantially controlled, rate into a fuel composition, for example, a hydrocarbon based liquid fuel, including, but not limited to, diesel, gasoline, kerosene, jet fuel, biodiesel and synthetic hydrocarbon based liquid fuels such as those obtained in the Fisher-Tropsch process. Optionally, these hydrocarbon-based liquid fuels can contain additives other than those being released by the apparatus of the present invention. These additives include, but are not limited to, oxygenates, antioxidants, anti-wear additives, cetane improvers, corrosion inhibitors, demulsifiers, detergents/dispersants, flow improvers, lubricating agents, metal deactivators and the like and mixtures thereof. The present methods comprise placing a container as set forth herein in contact with a fuel composition. When the container is exposed to a fuel composition, the fuel passes through, for example, diffuses through, the fuel-permeable element or elements and contacts a portion of the fuel additive composition. Release, preferably sustained, substantially controlled release, of additive or additives into the fuel composition is obtained, for example, by diffusion through the fuel-permeable element.
In one useful embodiment, the container in accordance with the present invention at least partially replaces and/or is integrated into the center tube of a filter assembly used to filter fuel, for example, while the fuel is being used. Thus, the container is effective to provide additive release and as a structural member in a filter assembly.
Commonly assigned U.S. patent applications Ser. Nos. (Attorney Docket No. D-2874) and (Attorney Docket No. D2959CIP), filed on even date herewith, are directed to somewhat related subject matter. The disclosure of each of these co-pending U.S. applications is incorporated in its entirety herein by reference.
Each and every feature described herein, and each and every combination of two or more of such features, is included within the scope of the present invention provided that the features included in such a combination are not mutually inconsistent.
Additional aspects and advantages of the present invention are set forth in the following description and claims, particularly when considered in conjunction with the accompanying drawings in which like parts bear like reference numerals.